Tuesday, April 17, 2012

Pheidole bicornis live in Piper Plants...what?????

Pheidole bicornis live in Piper Plants...what?????

Pheidole bicornis

Piper Plant


Pheidole bicornis consist of two different classes of arts: major and minor ants [2]. The majors help the minors in serving as a defensive escort and assisting in large food items. Major ants also help in defending the nest. They are also considered more powerful compared to the minor ants [3]. P. bicornis ants live inside of several different Piper plants. Some of these Piper plants are P. calcariformis, P. cenocladum, P. fimbriulatum, P. obiquum, and P. sagittifolium. These plants can get to one to two meters tall. Pheidole bicornis only house inside these plants in the tropics of Costa Rica, Panama, and Nicaragua. The piper’s leaf petioles have margins that expand producing an enclosed chamber, which the ant nests in. The plants consist of hollow stems and soft medullar piths, which the ants use to enter and exit the chamber. [2]

Ants living in the hollow stems
Ants using the hollow stems

Description of relationship:

The relationship between Pheidole bicornis and Piper ant plants is an example of an obligatory mutualistic interaction. The Piper plant produces white, pearl looking food bodies that are the main source of food for the ants. The food production can only be induced by the ants because plants grow in greenhouses. The ant helps in removal of herbivore eggs and other small herbivores by disrupting the production cycle of the herbivores. [2] Ants also help in nitrogen fixation in the plants. When an herbivore comes into the plant, the ant preys on the herbivore and gets its source of nitrogen rather than taking it from the plant [1].

Cost/Benefit Analysis:

Look at the description of Pheidole bicornis and Piper plants having a mutualistic relationship, both species benefit from each other rather harming each other. Cost and benefit in the relationship varies over time and space and the involvement of the partner [1]. Production in food bodies from the plants helps give ants a source of food and nutrients.  Since the ants can remove herbivores this benefits the plant in removing predators [2]. It is believed that in trophic regions (meaning there is higher nitrogen 15) the ants are beneficial to hosts because they obtain more nitrogen from herbivore preys [1]. This shows that there is some protection to the Piper plants from the P. bicornis in not taking all of its sources.  The plants also provides protection to the ant since it consists of an enclosed chamber where the ant nests.


[1] Feldhaar, Heike, Gerhard Gebauer, and Nico Bluthgen. "Stable Isotopes: Past and Future in Exposing Secrets of Ant Nutrition." Myremecological News. Myremecological News, Apr. 2010. Web. 17 Apr. 2012.
[2] Longino, John T. "Formicidae: Pheidole Bicornis." Academic Program Pages at Evergreen. Stefan Cover, 8 Jan. 2005. Web. 17 Apr. 2012. <http://academic.evergreen.edu/projects/ants/genera/PHEIDOLE/SPECIES/bicornis/bicornis.html>.

[3] Quinn, David L. "Genus Pheidole." Pogolumina.net. Pogolumina. Web. 17 Apr. 2012. http://www.davidlouisquinn.com/pogolumina_OA_pheidoleInfo.htm.